Messages in this thread | | | Date | Mon, 5 Feb 2024 09:17:45 +0000 | Subject | Re: [PATCH] cpufreq: Change default transition delay to 2ms | From | Christian Loehle <> |
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On 05/02/2024 02:25, Qais Yousef wrote: > 10ms is too high for today's hardware, even low end ones. This default > end up being used a lot on Arm machines at least. Pine64, mac mini and > pixel 6 all end up with 10ms rate_limit_us when using schedutil, and > it's too high for all of them. > > Change the default to 2ms which should be 'pessimistic' enough for worst > case scenario, but not too high for platforms with fast DVFS hardware. > > Signed-off-by: Qais Yousef <qyousef@layalina.io> > --- > drivers/cpufreq/cpufreq.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 44db4f59c4cc..8207f7294cb6 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -582,11 +582,11 @@ unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy) > * for platforms where transition_latency is in milliseconds, it > * ends up giving unrealistic values. > * > - * Cap the default transition delay to 10 ms, which seems to be > + * Cap the default transition delay to 2 ms, which seems to be > * a reasonable amount of time after which we should reevaluate > * the frequency. > */ > - return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000); > + return min(latency * LATENCY_MULTIPLIER, (unsigned int)(2*MSEC_PER_SEC)); > } > > return LATENCY_MULTIPLIER;
Hi Qais, as previously mentioned I'm working on improving iowait boost and while I'm not against this patch per se it does make iowait boosting more aggressive. ((Doubling limited by rate_limit_us) Since the boost is often applied when not useful (for Android e.g. periodic f2fs writebacks), this might have some side effects. Please give me a couple of days for verifying any impact, or did you do that already?
Kind Regards, Christian
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